Zika virus infection is a mosquito-borne viral infection. It is spread by the Aedes species of mosquito, most commonly Aedes aegypti and Aedes albopictus. Aedes mosquitoes also transmit dengue and chikungunya viruses. A mosquito becomes infected when it feeds on the blood of a person infected with the Zika virus. The mosquito is then capable of spreading the virus to other people through its bites.
The Zika virus can cause microcephaly in babies born to women who were infected while pregnant. Microcephaly is a rare birth defect in which the baby's head is smaller than expected, which can be related to problems with brain development. Other possible negative pregnancy outcomes include hearing problems and impaired growth in the newborn.
Zika virus infections have been reported since the 1950s in parts of Africa and Asia, and in the Pacific islands in 2007. In 2015, the Zika virus spread to Central and South America. Aedes species of mosquitos that are known to transmit the Zika virus are not suited to the Canadian climate, so Canadians are very unlikely to contract the infection at home, but cases have been reported of people returning to Canada with Zika infection after travelling to areas where there are Aedes mosquitos and active viral transmission.